Contact making wire clamp



Dec. 23, 1941. H. H. EBY 2,267,449

CONTACT MAKING WIRE CLAMP Filed Jun 29, 1940 JECTIOM-"E -E 54 4 'r 51 2 4 I g 1 58 g////// I 22 Z4 2! 56 ATTORNEY"? Patented Dec. 23, 1941 UNITED STATES. PATENT OFFICE CONTACT MAKING WIRE CLAW Hugh H. Eby, Jcnkintowmla'. Application June 29, 1940, Serial No. 343,122

Claims. (01. na -s40) This invention relates to contact-making wire clamps or connectors, and particularly to such devices as are generically designated binding posts.

With thed'evelopmentsof wire communications, especially in the art of war, it has become increasingly important that wire communication onceestablished, be maintained, substantially regardless of the viscissitudes to which the wires are subjected.

This has not yet become absolutely true, as it has been discovered that certain of the earlier forms of connectors established satisfactory electrical connection with wire only as long as nothing strained the wire. As soon as a soldier, or other moving object, imposes such stress on the wire as to cause it to be subjected to appreciable .longitudinal pull, such previous connectors either loosened the grip on the wire, or else as a result of the pull lost the electrical contact therewith, even though the wire might still be relatively anchored. Moreover such connectors after such wire pull were no longer available for subsequent fastening of other wires, as they had themselves suiiered distortion militating against such use.

It is among the objects of this invention to provide a cheap and rugged contact-making wire clamp; to provide a wire clamp arranged for easy and facile attachment; to provide a Wire clamp arranged to establish an intimate electrical contact withany sort of wire, whether insulated or uninsulated; to provide a wire clamp with gripping means guided and supported against lateral distortion as a result of wire pull; to provide a wire clamp arranged to center the wire to be clamped to facilitate engagement and electrical contact; to provide a wire clamp with gripping means larger in cross section than the wire to be gripped in one part and as large as the wire in the other part to insure tight grip thereon; to provide-a wire clamp with gripping contact-making members of such reinforced construction that even though under great pull a wire might be moved laterally of the clamp, the electrical contact will be maintained; to provide a wire clamping device having a single unitary member arranged both to clamp and to penetrate the insulation of a wire to establish electrical contact; to provide a wire clamp with an insulation and wire piercing gripping member, and

Fig. 1 represents a longitudinal transverse section through the assembled clamp of this invention according to a-preferred embodiment thereof in which regardless of its lower surface contour there is a vertical and a horizontal slot.

Fig. 2 represents a transverse section therethrough on line A--A of Fig. 1.

Fig. 3 represents a front elevation, partially in section through the device of Fig. 1 with a fragment of wire gripped therein showing itsdistortion under pressure. I

Fig. 4 represents a fragmentary section through a modified form of the clamp,showing a V shaped bottom of the slot.

Fig. 4A represents a fragmentary elevationpartially in section of the clamp of Fig. 4 with an insulated wire pierced and gripped thereby.

Fig. 5 represents a fragmentary section of a further modified form of clamp showing a single incliilied slot in place of the compound'slot of Fig.

Fig. 6A represents a fragmentary elevation, in part section, of the clamp of Fig. 6 gripping a wire.

Figs. 6 and 7 represent respectively fragmentary elevations partially in section of a clamp ac cording to Fig. 1 engaging, establishing contact with, and gripping an insulated wire and a smaller bare wire, to show the operation of the device, with the cap removed for clarity.

Fig. 8 represents a fragmentary elevation, 'partially in elevation of a clamp having a bluntended stud engaging a relatively thick wire, in an initial stage of compression.

Fig. 9 is a view similar to Fig. 8, showing the anchored engaged relation of the parts to a stranded wire.

Fig. 10 represents a'fragmentary longitudinal section through a modified form of clamp.

The wire-gripping electrical connector preferably comprises a unitary device having no disconnectible parts, so as to facilitate use of the connector for military purposes. In the purely illustrative device shown in Fig.1, which will be relied upon for the broad purposes of disclosure, but which is obviously susceptible to wide variations in actual construction, some of which will be pointed out later herein, a solid integral base I0 is provided, having a lower terminal end I l preferably comprising a threaded shank, leading a into the flange I2. A generally hollow cylindrimany other objects and advantages willbecome cal element l3 extends axially of the flange I2 opposite to the threaded shank II, and the outer free end I4 thereof is preferably completely cylindrlcal in a closed cylinder having an internal axial bore l5, and having the external threads I. The side of element or base ID has a transverse relatively horizontal or lateral slot opening- I! forming an entrance for wires.'which communicates with the through axially'elongated relatively vertical transverse slot l8 of such extent axially of the base as to form an internal arcuate or other lower shoulder or abutment 20 immediately below the slot opening II to prevent undesired lateral withdrawal of wires after disposition in the slot iii. In the preferred embodiment the axial bore I5 in the base is prolonged axially across the axial transverse slot l8 and terminates in a flat ended seat depression or hole 2|, and the bore is preferably of greater diameter than the width of slot i8 and is preferably symmetrical thereof. The flat surface of the seat depression 2| may be at any other point but is preferably substantially tangential to the preferably arcuate lower surface 22 of the vertical'or axial slot i8. In order to flrmly anchor the base in whatever it may ultimately be secured and to hold it against rotation, a pin 23 is provided extending from the lower surface of the flange l2. In the preferred embodiment the flat seat depression 2| has a concentric recess 24 extending across the flange line. into the shank if the length of the pin to be described should be such 25 substantially transverse of slot l8 for a purpose to be described.

In the modification of the baseelement shown in Fig. 4 all of the parts are preferably the same as has just been described, except that the slot ll has angularly divergent walls, respectively 26 and 21, meeting in an apex at the lower endrof the slot as at 28.

In the further modification shown in Fig. 5, the compound slot shown in Figs. 1 and 4 comprising the horizontal slotopening i1 and the vertical slot i8, has been formed as the inclined slot 30, as a form into which wires can be placed readily and easily locked, and which under some circumstances might be considered as easier to fabricate with the machinery available. The operation of this slot will become more evident as the description proceeds.

Returning now to Fig. i there is shown in section an externally knurled hollow cap 3| internally threaded as at 32 so as to threadably engage the threads |8 of the base i0, having the depending bendable flange 33 preferably bent about the external surface of the element N below the threads It. so as to form a positive stop to the removal of the cap. A stud 34 preferably, although obviously not essentially integral, depends from the end of the cap to termination in 9; preferably substantially flat end 35 and is arranged to move downwardly in the bore ii of the base. shearing across the shoulders 25 to seat in seat depression 2|. The stud is preferably such as to have a sliding but guided laterally reinforci 8 fit in the bore l5. In one form of the invention the stud end is finished substantially flat as shown in Figs. 8 and 9 and the operation ofthe invention in such a manner as to engage suitable wires will be described. However it is preferred to mount an axially extending pointed pin 35 in the flattened end or to continue the stud in an integral continuation in such pin if desired. It will be clear that the pin 36 will normally seat in the recess 24 in the seated or closed cap position.

In the fragmentary views which will now be described it will be assumed that wires of various characteristics will have been inserted in the respective slots and have been engaged by the end of the studs, both with and without the elongations in the form of pins.

Assuming that the wire 38 to be engaged is of small gauge but with heavy insulation 40,- the operation will be as shown. in Fig. 6 in which .with the wire moved laterally through slot opening into slot l8, the cap will be turned to force the end of the stud against the wire, and the wire will be centered in the-slot by' the convergent walls (whether arcuate or angular), the pointed pin will be forced through the insulation into the wire 38 to establish intimate electrical .contact of the wire and the connector while simultaneously the blunt or squared end 35 of the stud will have engaged the insulation 40 and begun to crush it, causing it in effect to flow downwardly toward the seat depression 2|, and laterally into the bore extension, across shoulders 25, disposed substantially transversely of the wire, exerting shearing action to dig the shoulders 25 into the insulation while forcing the insulation into the spaces or depression 2| behind the shoulders, as shown in dotted lines in Fig. 6A to firmly anchor the wire to the connector by enhanced frictional effects between the parts. If the pressure is sufficiently great the crushing of the insulation will be imparted to the wire to distort it out of its initial concentric alignment to contribute to the increased frictional gripping of the parts. The forcing of the pin 36 through the insulation and into the wire will cause some distortion of both insulation and wire to enhance the interlocking relationship.

It is contemplated that in many instances the wire will first be scraped of insulation as shown in Fig. '7, in which event the pin 36 will assist in pushing the wire toward either the front or the'rear of the vertical slot while permitting the flattened end 35 to exert its crushing contactmaking anchoring function. In certain cases where it is known that wires of small gauge are to be encountered a pin of larger base may be used to so crowd the wire laterally as to force it more certainly over the shoulders of the contact seat. In the alternative similar results are achieved by simply making the seat depressions 2| deeper to a position parallel to the tangential, and in this case there is no interruption of the vertical shoulders and each wire is given a certain amount of shearing stress. As it is not desired to cut the wires off, the exposure to shoulder shearing stress will be limited to a degree not more than that required to merely bite into the wire. In the case ofinsulated rhultiple strand connectors, cables or wires the ability of the pinto penetrate and anchor the strands, instead of pushing them aside as in the last described figure, will be obvious.

In the case of the V-shaped bottom to the slot l8 it will be evident that the descending pin will penetrate the small insulations as well as the large centrally of both to engage the concentric wire within the insulation while the convergent as well as scraped or uninsulated wires.

Theanalogous functioning of the forms of the invention which have no pins will be clear, but for convenience reference may be made to the fragmentary disclosure of. Fig. 8 in which a large bare wire 4! is hown as being engaged by the connector. The shearing stresses, the enhanced frictional bite attaching thereto, will be clear. An analogous operation upon bare stranded wire 42 is indicated in the fragmentary disclosure of Fig. 9.

It is a further feature of the invention under desired conditions to utilize the fiange 33 on the knurled cap 3| to engage and exert shearing stress upon that portion of the wire extending laterally from the connector as the stud is doing the same centrally of the base, to enhance the frictional grip on the wire, as shown in Fig. 3.

The important result of maintenance of complete electrical contact despite any lateral slippage of the wire relative to the connector is secured by the invention, and the quickness of operation and attachment, the freedom from use p of multiple parts for the purpose, and the strength of the assembly will be obvious. It is to be remembered that with the stud guided in i the bore leading right to the upper surface of the shown with a base Ill having a lower portion' formed like any of the preceding figures (illustratively like Fig. 1) having an anchoring stud ll, flange i2, horizontal slot i1, vertical slot I8, cylindrical extension l3, and a bore extension seat 2|. The cylindrical extension M has a bore i5 to receive and guide an anchoring stud 34' having the lower substantially fiat end 35 and sharpened extension 36 arranged to seat in seat depression 2i, and the upper end of stud 34 is threaded as at 4| and engages threads 42' in the upper portion of the extension, separated from bore I5. A knurled cap 43 on the upper end of the stud enables it to be moved axially of the base in a manner similar to and with a result analogous to that of Fig. 1 for instance.

It will be understood that the flange 33 of the cap 3| of Fig. 1 may terminate at any level relatlVe to the termination of the internal stud 34 or point 36, so as to augment the grip on the wire by compressing it in shear against the bottom of the slot l8 at the ends of the slot, if this is desired, or to merely serve to hold the cap on the base without any appreciable contact with the clamp-engaged wire.

I claim as my invention:

1 A contact making wire clamp consisting of two members mounted in telescopic. relation, one of said members being relatively fixed and havin a slot, a depression, an opening, and a bore, said slot extending transversely through said member and having a substantially arcuate wall at one side, said depression passing through said substantially arcuate wall to form oppositely disposed shoulders, said opening communicating laterally with said slot to permit a wire to enter said slot, and said bore extending axially of said member from the opposite side of said slot from said depression, the other of said members being adjustably mounted on the fixed member and having a plunger guided by said bore to enter said slot to compress saidwire over said shoulders and into said depression to thereby resist endwlse movement of said wire, and a piercing pin on said plunger to penetrate said wire. 7

2. A contact making wire clamp consisting of two members mounted in telescopic relation, one of said members being relatively fixed and having a slot, a depression, a lateral opening, and a bore. said slot extending transversely and communicating with the lateral opening to permit a wire to be inserted into said slot through said opening, the lower surface of the slot being curved to support a wire when in {said slot, said bore being of greater diameter than the width of said slot and extending into the slot axially on one side thereof to form axial shoulders therewith, said depression being locatedinsaid curved lower surface of the slot on the/side axially opposite to said bore and forming "shoulders to extend substantially transverse of a wire in said slot and merging into said axial shoulders, the other of said members being adjustably mounted on the fixed member and having a plunger guided by said bore to enter {said slot'to compress a wire over both sets of shoulders and into said depression and bore extension whereby said shoulders engage the wire to resist endwlse relative movement of the wire, and a piercing pin on said plunger to penetrate the wire.

3. A contact making wire clamp'consisting of two members mounted in telescopic relation, one of said members being relatively fixed and having a slot, a depression, an opening, and a bore, said slot extending transversely through said member and having a substantially arcuate wall at one side, said depression passing through said substantially arcuate wall to form oppositely disposed shoulders, said opening communicating laterally with said slot to; permit a wire to enter said slot, and said bore extending axially of said member from the opposite? side of said slot from said hole, the other of said members being adjustably mounted on the fixed member and having a plunger guided by said bore to enter said slot to compress said wire over said shoulders and into said depression to thereby resist endwlse movement of said wire.

4. A contact making wire clamp consisting of two members mounted in telescopic relation, one of said members being relatively fixed and having a slot, a depression, a lateral opening, and a bore, said slot extending ,ransversely and communicating with the lateral opening to permit a wire to be inserted into said slot through said opening, the lower surface of, said slot being substantially planar in profile onja section longitudinal of the slot and being substantially non-planar in profile with downwardly convergent surfaces on a I section transverse of the slot and serving to support a wire when in said slot, said depression being located in said lower surface and having a bottom surface of a different profile from the profile of said convergent lower surface transverse of the slot so as to form shoulders of varying height extending substantially transversely of said slot, said fbore extending toward the slot opposite to said, depression, the other of said members being adjustably mounted on the fixed memberand having a plunger guided by said bore to enter said slot to compress such wire over said shioulders to resist endwlse movement of such w re.

5. A contact making wire clamp consisting of two members mounted in telescopic relation, one

or said members being relatively fixed and having a slot, a depression, a lateral opening, and a bore, said slot extending transversely and communicating with the lateral opening to permit a wire to be inserted into said slot through said opening, the lower surface of said slot being substantially planar in profile on a section longitudinal of the slot and being substantially nonplanar with downwardly convergent surfaces in profile on a section transverse of the slot serving to support a wire when in said slot, said bore extending toward the slot opposite the depression, said depression being located in said lower surface and having a bottom surface substantially tangential to the downwardly convergent surfaces so that the substantial plane of the profile longitudinal of the slot is substantially maintained across said depression to form an anvil against which the main thrust applied to the wire is received, said depression having walls substantially parallel to the axis of the bore and forming with said lower surface fight-angled shoulders of varying height increasing from the point of substantial tangency transversely of the slot, the other of said members being adjustably mounted on the fixed member and having a plunger guided by said bore to enter said slot to compress a wire against the anvil portion and to distort same laterally of the anvil portion into contact with said right-angled shoulders to resist endwise movement of such wire.

HUGH H. EBY. 

